Constant-pressure water replenishing device

The invention relates to the technical field of high-temperature water waste heat recovery, and discloses a constant-pressure water replenishing device which comprises a water tank provided with a water supply valve, a drain valve, a water level monitoring device and a pressure monitoring device. The constant pressure tower is arranged above the water tank and communicated with the water tank, and an exhaust valve and a pressurizing valve connected with a pressurizing device are arranged on the constant pressure tower; the water replenishing valve is arranged on the water tank or the constant pressure tower and is used for replenishing water into the water tank; the programmable control device is connected with each valve on the water tank and the constant-pressure tower and the water replenishing valve, when the water level in the programmable control device is low, the water replenishing valve is opened to replenish water, when the water level in the programmable control device is high, the drain valve is o